Process of concentrating ores by flotation



Patented Dec. 29, 1931 UNITED STATES PATENT oFFlCl-lg--.

HERBERT A. LUIBS, OF PENNB GROVE, NEW JERSEY,

AND ARTHUR L. rox, OF

WILMINGTON, DELAWARE, ASSIGNORS TO E. I. DU PON'I. DE NEMOURS & COMPANY,OI WILMINGTON, DELAWARE, A CORPORATION 01' DELAWARE PROCESS OIGONCENTRA'HNG OBES BY FLOTA'IION No Drawing.-

' This invention relates to improvements in the process of concentratingores and minerals by flotation, particularly by the use of certain typesof compounds which have not hitherto been employed for this purpose. Ithas been found that the concentration of ores by flotation can begreatly facilitated if we use in the flotation operation certain organiccompounds containing the groupSH.

It has been discovered that marked flotation effects are obtained withorganic complounds containing the group-SH, in which may be replaced bya metal, as the alkali metals or lead, said group being attached to acarbon of an organic radical which, if it is an aryl radical, ispreferably free from amino groups ortho to the mercapto group, saidcarbon being in turn attached to at least one other carbon atom or tohydrogen.

All of these compounds are effective but some to a less degree thanothers. Many of them are extremely powerful flotation agents. Thealiphatic mercaptans, for example, are

excellent flotation agents, whether they are normal or branch-chaincompounds. Thev .cane and anthraquinone series are effective flotationagents, such for example as anthraquinone alpha mercaptan. Partially orcompletely hydrogenated cyclic compounds are also useful. As examples wemay mention decahydro-naphthyl-mercaptan, tetrahydro-naphthyl merca tan.Heterocyclie compounds are also e ective, such for ex- Application filedDecember 13, m1. Serial No. 289,816.

ample as thiophene mercaptan, 'furyl mercaptan, pyrldyl mercaptan,thionthrene 'mercaptan, quinoline mercaptan. Such compounds also asbenzyl mercaptan and furfuryl mercaptan may also be used.

In order to illustrate the effectiveness of these compounds, thefollowing examples of processes involving their employment inrepresentative flotation operations are submitted:

Example 1 Five hundred grams of copper ore (0.95% Cu) from theInspiration Consolidated Copper Company were ground in a pebble millwith 450 cc. of water and 0.35 g. of hydrated lime. This pulp wastransferred to a mechanically agitated flotation machine and conditionedtherein for. 1 minute with pine oil and .005 g. of ethyl mercaptan.Water was then added to give a pulp of approximately solids. Thisdilution caused circulation of the pulp thru the spitz, and frothformation. The froth was removed for 10 minutes. A similar test was madeusing isoglieiilyl. mercaptan. The results are tabulated Percent PercentPercent Product a :6 ggs: Cu in Cu re- Hate tailings covered Ethylmercaptan .025 13. 23 0.33 69.3 I20 mercaptan .050 11.55 0.36 67.2

Emample II Five hundred grams of copper ore (0.95% Cu) from theInspiration Consolidated C0 per Company were ground in the pebble millwith 450 cc. of water and 0.35 g. of hydrated lime. This pulp wasdivided 'into three parts and transferred to mechanically agitatedflotation machines and each part conditioned therein for one minute withpine oil and one of the aromatic mercaptans listed in the followingtabulation. Water was then added to ve a pulp of approximately 20%solids. his dilution caused circulationof the froth thru the spitz, andfroth formation. The froth was removed for 10 minutes. The results areindicated below:

Per cent P t Product Cu in Cu relbsJton concentamngs covered irate Blanktest-pine all alone..." 0. 16 2.28 0. 90 7. 0 thiocreeol (with pine oil)0. 014 22. oo 0. 39 59. 7 hlophenol with pine oil) 0. 01B 10. 70 0. 3268. 0

Thio-b-naphthol (with pine oil) 0. M 9. a0 0. 45 54. 5

0.24 lb. of pine oil used, in othert'ests 0.16 lb. used.

iso-am l mercaptan.

methy -mercaptan. propyl-mercaptan. n-butyl-mercaptan.isopropyl-mercaptan. p-dichlor-phenyl-mercaptan.

v p-dichlor-phenyl-dimercaptan.

o-dichlor-phenyl-dimercaptan.. I p-methyl-iso-propyl-phenyl-mercaptan.mercapto-ortho-cresol. benzyl-mercapta-n.

Of the many compounds which fall within the scope of our invention,thiophenol may be mentioned as one of our preferred embodiments.

We have also found that remarkably strong flotation action is obtainedwith compounds of the general type sn in which H may be replaced by ametal, and

in which R is an organic radical, to a carbon of which is attached thegroup s -c sH The carrying into efiectLof the process with to severalsuch reagents is Illustrated below.

Example III Five hundred grams of copper ore (0.95%

Cu) from the Inspiration Copper Company 5 were ground in a pebble millwith 450 cc.

water and 0.35 g. hydrated lime. The pulp was then transferred to amechanically tated flotation machine, and conditioned or one minute withine oil and one of the flotation a cute in icated below. Water was thenad ed to give a pulp of approximately 20% solids. This cause circulationof the pulp throu h the spitz, with froth formation. The froth wasremoved for 10 minutes.

The amounts of reagent used and the recovery of copper are shown below1n connection with each specific reagent employed:

Amt. Peromt Pu'cmt P.- out Cuin Culn Ounoonct covered ton Mg salt 01dithiobenzoic acid (with pine oil) cm 11.1 an 00.1 Crude dithioiuroicacid (with pine oll) ace 11.0 am can Zinc salt of dithioiuroic acid(with pine oil) M! 12.1 an no Sodium salt of dithiohydroxynaphthoic acid(with pine oil) 0.02 as us 514 Ne salt of dithioproplonlc acid (withpine oil) cos 14.9 as 41.0 Blank test (pine oil alone)..." an 2.: 0.001.0

'o.24 lb. of pine oil used W or usual am a, the use of um pine oilcausing the inclusion of more gangue in the concentrate, therebylowering the percent coppc thu'eln.

Many other compounds of the type may also be used. As examples we maymention dithiosalicyclic acid, dithiotoluic acid,p-methoxy-dithiobenzoic acid, dithiobutyric acid, dithiogluconic acid,'dithioacetic acid, dithiovaleric acid, or their salts. Naturallycompounds of this type are not all equally efiective. Among ourpreferred compounds of this particular grou are the magnesium and sodiumsalts of dithiofuroic acitci1 and the sodium salt of dithiobenzoic ac1The new flotation agents are also, in general, adapted for use inselective flotation operations but some of them, for example, thiophenoland thiocresol, and the magnesium salt of dithiobenzoic acid, have theproperty, to a very remarkable degree, of selective flotation and may beemployed to advantage, for example, in floating copper sulfide inpreference to iron sulfide.

It is obvious fromthe foregoing illustrations that the class of com undsdescribed constitutes unusually e ective flotation agents. Thesecompounds are adapted for use over a wide range of conditions. Whereemployed for selective flotation with complex ores the ores may'ofcourse contain more than two minerals and the process of selectioncarried out by merely repeating the flotation step for each ore itisdesired to recover.

The usual conditioning agents may, of course, be employed with the newflotation agents, as illustrated in the examples.

, froth flotation operation It. will be understood that the invention isnot limited to thespecific classes of compounds or the specificcompounds themselves mentioned above for illustrative purposes, but manyother compounds not mentioned above, but which come within the scope ofthe following claims, may be employed. It

is to be understood that where the terms'ali-- is attached.

2. In the concentration of ores and minerals by flotation, the stepwhich comprises subjecting the ores, in the form of a pulp, to a frothflotation operation in the presence of a compound of the type in whichH'may be replaced by a metal, and R is an aromatic radical, to a carbonof which the group is attached.

3. In the concentration of ores and minerals by flotation, the ste whichcomprises sub ecting the ore, in the orm of a pulp, to a in the presenceof a compound of the type sn', inwhich H may be replaced by a metal, andR is a radical of the group consisting of aliphatic, aromaticandheterocyclic radicals, to a carbon of which the grou is attached.

4. In the concentration of ores and minerals by froth flotation, the stewhich comprises subjecting the ore, in t e form of a pulp, to aflotation o eration in the presence of a dithiofuroic aci compound.

5. In the concentration of ores and minerals by froth flotation, thestep which com- 7 prises subjecting the ore, in the form of a pulp, to aflotation operation in the presence of a salt of dithiofuroic acid.

6. In the concentration of ores and minerals by froth flotation, thestep which comprises subjecting the ore, in the form of a pulp, to aflotation operation in the presense of a compound of the groupconsisting of dithiofuroic acid and dithiobenzoic acid compounds.

7. In the process of concentrating ores and minerals, the step whichcomprises subjecting an ore containing copper and iron, said ore beingin the form of a pulp, to a froth flotation operation in the presence ofan organic compound adapted to raise copper sulfide and depress ironsulfide, said compound being of the type lit-0 in which H may bereplaced by a metal, and

R is an organic radical, to a. carbon of which the group is attached.

8. In the process of concentrating ores and minerals, the step whichcomprises subjecting an ore, containing at least two metals, in the formof a pulp to-a froth flotation operation in the presence of a compoundadapted to raise one metal and depress another, said compound being ofthe group. consisting of dithiofuroic acid and dithiobenzoic acid.

In testimony whereof we afiix our signatures.

HERBERT A. LUBS. ARTHUR L. i

